As discussed in U.S. patent application Ser. No. 08/195,759, many existing instant-win lottery cards or tickets comprise a paper substrate to which foil is laminated. The foil is then coated both to minimize oxidation and to provide an ink-retaining surface onto which symbols may be printed. At least one additional sealant may be applied to the inked surface to protect the printed symbols, and a single opaque metallic latex covering used to obscure them from view. Post purchase or distribution, the ticket bearer, or player, typically removes ("scratches off") the latex covering to reveal the hidden symbols. Existing tickets often further include at least one "release" coat interposed between the latex covering and protective coating to facilitate the removal of the latex covering in use.
The paper substrate and foil combination employed in these existing tickets provides an opaque base onto which the hidden symbols are printed. In particular, introducing foil into the ticket prevents unscrupulous players from viewing the printed symbols by examining the ticket before a light source, a process known as candling. Using the non-porous foil also makes the ticket base more durable (and thus less susceptible to mechanical manipulation or damage) and prevents the hidden images from wicking to the underside of the base (where they might become visible).
Existing foil-based tickets are difficult to recycle, however, as the metal laminate interferes with conventional paper recycling processes. Although including foil in these cards or tickets reduces the possibility of electrostatic tampering with the hidden images, it also prevents electrostatic printing techniques from being employed, reducing the variety of graphics available for use. Empirical evidence further suggests that laminating foil to recycled paper fibers generally decreases the quality of the print surface as well.
A recently-introduced instant-win ticket appears to omit foil from its base, opting instead for a water-based black coating approximately one micron thick and comprised of carbon, chlorine, and calcium. This black coating is believed to be either identical or virtually identical to the composition of the ink used to print the hidden images on the ticket, thus diminishing the possibility that an unscrupulous player could distinguish the hidden images from the coating through candling. To contrast the hidden images from the black base coating once properly revealed, the ticket interposes a lighter-colored coating between them. This ticket also appears to include only a single (pink) coating over the hidden image for sealing it, potentially reducing the time necessary for unscrupulous players to scratch off the latex covering and remove both the sealant and hidden images of losing tickets (in order to substitute winning images for them). The black coating contains no fugitive dye to provide evidence of wicking, moreover, as none is necessary because of the coating's similarity to the ink used to print the hidden images.